Means for extracting or expelling water and other liquids from yeast suspensions



Marchz, 1946. SMQ ROSENQWST '2,397,436

MEANS FOR EXTRACTING 0R EXPELLING WATER AND OTHER LIQU-Ins l FROM YEAST sUsPENsIoNs il w i 5y March 26, 1946. s. o. RsENQvlsr 2,397,436-

' MEANS FOR EXTRACTING OR EXPELLING' WATER AND OTHER LIQUIDS FROM YEAST SUSPENSIONS ATTORNEY Patented Mar. 26, 1946 WATER AND OTHER v'LIQIDS V"FROM TIIEASI` SUSPENSIONS Sven Olof .Rosenqvish Rotebro, `Sweden, assigner -to 'Svenska 'Jstfabriks Aktiebolaget, Stockholm, Sweden, a company of Sweden Application 'March 127, 1942, Serial No. '436;542 'In Sweden February .221, .1941

This invention relates to a process and. anapparatus 4for `extracting Yor .expelling water and other .liquids from yeast suspensions. Hithcrto, it :has been usual to Vdewater yeast Ysuspensions such ,as ryeast concentrate `by :pressing in filter presses zand, incertain cases, also in `rotating vacuum filters. The .first-mentioned method, however, cannot be performed .in continuous operation, rand, moreover, the apparatus involved are rendered bulky and heavy. 'On the rother hand-it is not possible wlith 'the Aaid of rotating vacuum :filters .to attain the consistency or 4degree of 'dewatering which .is Adesirable for certain purposes. AIt should also be noted that `vacuum lters'are ,expensivein manufacture, inasmuch as they mecd Ato be :constructed =so as to withstand an internal vacuum.

.These disadvantages are `obviated through the present invention, whichenables the yeast to be dewatered vto the desired ydegree Ior consistency entirely l:satisfactorily yincontinuous operation. According to the main .features of the invention the yeast-,suspension is introduced-into -a -movable filter Lchamber .operating with internal pressure, and is :causedz'to depositaor adhere to thefinternal wall of such chamber, liquid being :expelled or separated :from the `yeast lby means of the pressure :prevailing inthe fiilten whereupon the `dewatered yeast lmass is removed from the filter chamber. By thislmethod'the drawbacks incident tothe 'presses Vhitherto-employed in the Lmanufacture of yeast 4are avoided, in that the yeast intended to 'be :dewatered `will not, according to the invention, vbe 4subjected lto any :material internal friction -during the` pressing ordewatering operation, vand, Aas ya consequence of this fact, its consistency willnot-involveany difficulties in the 'takingioff operation or in the continued treatment in packeting machines and so forth upon the termination of the dewatering process. Furthermore," the use of alter `with an internal'pressure involves the advantage that'it will be possible without difficulty to use fa pressure as high-as required for the desired 'degree of water expulsion, without it be'ing necessary to 'makethe construction complicated or'expensive from the point of view of strength.

`Thelinvention also relates to means suited for carrying thelabove-mentioned method into effect, saidmeans comprising one or more movable filter chambers voperating with an internal pressure, supply means lto "apply the yeast vsuspension onto theinner"surfaceof'the'lter chamber, adjustable means 4Vfor-taking off theyeast from said surface after vlia-ving 4beenfdewatered to thedesired de-v gree, and means in the form ,of a `continuously driven conveying 'member (such as `a conveyor screw or the like) to ndischarge the -dewatered yeast from the 'filter chamber.

Further Afeatures vand advantages of fthe invention will appear from the vrfollowing description with reference to the accompanying 4drawings illustrating a drum `1ter by wayof diagrammatic representation, said filter rbeing adapted for use in connection with the `process Aaccording to 'the invention. Fig. i1 .shows a longitudinal. section fof the filter and Fig. 2 a'crosssection thereof. lFigs. 3 and 4 represent some rdetail views. Fig. 5 shows a diagrammaticalcrossesection .through a :modied embodiment fof 'the invention.

In 'the example :of embodiment shown, the .drum I is ymounted in a fframe .2, v:and preferably l,comprises an approximately :cylindrical (or polyhedrical) central portion la :and two, preferably Asemi spherical head members lb, il-c connected thereto. The cylindrical ,portion la `consists of va perforated casing or envelope and is (preferably on the inside thereof) provided with lter cloth 3. This lter cloth may be attached between the flanges lindrical portion la. A packing .5 isprovided be tween the reinforcement 4 and said headmember Ib, and the requisite tightening effect will `be obtained in operation by the Vfact that .the head member plate is pressed Voutwardly against .the packing 5 by the pressure prevailing .within the drum. "If it is desired toremove `the headmember Ib, this is simply effected bypullingout thesame after `the pressurehas been relieved. Obviously,

other tightening and attaching means .may come into consideration as well.

The drum is vbrought vinto rotary movement from any suitablesource of power vas indicated diagrammaticall-y at '6. The source of VVpowe;` .is adapted to drive -a .sleeve 1 connected with the head member lc. Provided within this sleeve is a conduit T8 for compressed air orcompressed gas, as well as a conduit 9 for the yeast Amass cr suspension which is tobe dewatered orseparated from water or other liquid. "The pressure conduit 8 opens at 'asuitable 'point kwithin 'the drum, so as "to `maintain -an air or gas pressure within said Y drum. The conduit 9 is preferabiy connected i vto one or more spraying pipes I0, or toV any other 3 spraying means provided in the propinquity of the filter surface, for instance at the upper portion thereof, but other places may come into consideration asfwell. The suspension entering through the spraying pipe adheres to thelinside of the filter Wall and follows with the latter in the rotation thereof, and during this rotation the layer of suspension deposited is subjected to the pressure (above atmospheric) prevailing within the drum, so that liquid will be expelled Y or extracted in the desired quantity. The filter cake formed is scraped or taken off continuously l by means of a scraping or taking off device which `is preferably arranged at a peripheral distance as great as possible (counted in the direction of rotation' of the drum) from the point Vat which `the suspension is applied onto the filter cloth.

By this means a large turn-out capacity may be obtained. In the example of embodiment shown,

the scraping device consists of a knife II. As

` it is important that this knife be adjustable relatively to the filter surface to facilitate a more `or less thick basic layer to be left on the filter cloth, the knife is preferably connected to an loperating device adapted `to be actuated from the outside and consisting, for instance, of a linkage I2 connected to a sleeve I3 or the like adapted to be turned independently of the rotation of the drum. The turning movement may be effected `by means of a handle I4 on the sleeve.

The mass scraped off falls down into a trough I5 beneath the knife and is fed from the drumV in any suitable manner, for instance by means of a conveying helix I6 adapted to convey the material out through a nozzle IT at one end of the drum. This nozzle may be connected directly with a packeting machine or the like for the finished yeast material. Preferably, the shaft I8 of the screw I6 extends throught-.he sleeve I3 ified in a number of Ways, Without departing from the scope of the invention. In many cases it may be found-suitable to arrange one or more vsuction chambers on the outside of the lter in the zone Where the mass is appliedonto the filter surface. Such external yvacuum involves the advantage that the mass will adhere more easily to the filter surface. An embodiment of this kind is shown in Fig. 5, in which the said suction chambers shown at are connected with a suction conduit 2I communicating with a sourcey of suction 22. o Y

As many changes could be made in the above method and construction and many apparently Widely different embodiments of the invention could be made without departing from the scopeV moreover, intended to include air pressure Within the scope thereof.

= pressure in said chamber, a supplying device extending into said filter chamber to apply yeast suspension onto the inner surface of said Wall section, an adjustable scraper arranged in said Achamber in juxtaposition to said inner surface to take the dewatered yeast 01T said inner surface,

Y,and a continuously driven conveying device for receiving the dewatered yeast from said scraper and for removing the yeast from the filter chamber, and means for adjusting said scraper during the filtering operation.

2. Means for dewatering yeast suspension, comprising in combination, a movable drum constituting a filter chamber and including a perforated Wall section through which filtered liquid may pass, means for vestablishing superatmospheric gas pressure therein, a spraying device extending into said chamber for applying yeast suspension onto the inner surface of Vsaid wall section, ad-

justable means arranged in said chamber inr juxtaposition `to said inner surface to take the dewatered yeast off said inner surface, and a continuously driven conveying device having an inlet in substantialV alinement with said adjustable means to receive and to remove the yeast from the filter chamber, said taking-olf means being adjustable relatively to the said inner surface, and means for eiecting said adjustment operable from the outside of the said chamber.

3. Means as claimed in' claim 1, and at least one suction chamber arranged on the outside of said filter chamber in the propinquity of'said supplying device for the purpose of maintaining.

an external vacuum thereabout. l

4. Means for dewatering yeast suspension, comprising in combination a rotatable drum consti-Y tuting a filter chamber and including a perforated wall section through which filtered liquid may pass, means for establishing superatmosphericV gas pressure in said chamber, a supplying device extending into said chamber for applying yeast suspension'V onto the inner surface of said Wall.

section, taking-off means adjustable relatively to said inner surface and located in said chamber at a peripheral distance from said supplying device approximately amounting to a whole revolution in the direction of rotation of said filter chamber, means for adjusting said taking-olf means during the filtering operation, and continuously driven conveying means having -an in- Y let to receive and to remove the devvatered yeast from the said filter chamber.

5. Means for dewatering yeast suspension, comprising in combination a rotatable drum constituting arfilter chamber and including a perforated Wall section through which filtered liquid may pass, means for establishing superatmospheric gas pressure in said chamber, a supplying device extending into said chamber for applying yeast suspension onto the inner surface of said Wall section, a taking-off scraper vfor the rdewatered yeast and adjustable relatively vto said inner surface and located in said chamber at a peripheral distance approximating a wholerevolution of 4said filter chamber from said supplying i device, means for adjusting said scraperloperable tinuously driven screw conveying means having an inlet in substantial alinement with said adjustable scraper to receive and to remove the dewatered yeast from said lter chamber.

6. Means for dewatering yeast suspension, comprising in combination a rotatable drum constituting a lter chamber and including a perforated wall section through which ltered liquid may pass, means for establishing superatmospheric gas pressure in said chamber, a supplying device extending into said chamber for applying yeast suspension onto the inner surface of said Wall section, a taking-off scraper for the dewatered yeast and adjustable relatively to said inner surface and located in said chamber at a peripheral distance approximating a whole revolution of said rotatable filter ch'amber from said supplying device, means for adjusting said scraper operable from the outside of said lter chamber, a continuously driven screw conveying means having an inlet in substantial alinement with said adjustable means to receive and to remove the dewatered yeast from the filter chamber, and at least one suction chamber on lthe outside of the lter chamber in the propinquity of the supplying device for the purpose 0f maintaining an external vacuum thereabout.

SVEN -OLOF ROSENQVIST. 

